PharmaSeq provides ultra-small microtransponders and a fluidics-based, bench-top flow reader as tools to perform complex bioassays. The assay involves three phases: conjugation or synthesis of probe molecules on the microtransponder surface, the binding reaction with target molecules labeled with a fluorescent dye, and the readout of the microtransponders by the flow reader. A microtransponder is an integrated circuit with an electronically stored ID (64 bits) and the capability to transmit the ID by radio frequency. Each chip is composed of photocells, electronic memory and antenna. In its memory, the chip stores information that identifies the sequence of the genetic material attached to the chip. The transmission of information occurs upon illumination by laser light, which powers the chip. PharmaSeq developed two versions of microtransponders, namely 500x500 and 250x250 microns in size. The flow reader has two functions: to read each microtransponder's ID and to measure fluorescence from the reporter molecules bound on the microtransponder's surface. The fluidics system directs microtransponders one by one to the flow chamber, where the chips are illuminated by light, the microtransponder ID is read, and fluorescence is measured. The main goal of the present project is to build a two-color instrument for reading microtransponders to permit quantitative bioassays. The instrument will be capable of simultaneously reading fluorescence from microtransponders on two wavelengths, 570 nm (Cy3 dye) and 670 nm (Cy5 dye). The project will involve significant changes to the existing instrument, in particular, addition of a new laser and a photomultiplier, redesign of the optical system, and other hardware changes, as well as a rewrite of the instrument and data analysis software. The Specific Aims of Phase I are to prove feasibility of building the two-color instrument, and they include: 1) Formulate a detailed design of prototype instrument, 2) Build the instrument, 3) Test the instrument extensively and establish its characteristics, 4) Demonstrate a two-color assay by performing expression profiling on commercially available mRNA from two different tissues. The major benefit is to provide a reference and to provide accurate comparison between two samples. The instrument will enable, in particular, a two-color expression profiling experiments as well as many other types of assays currently done on microarrays or flow cytometers. [unreadable] [unreadable]